E2F transcription factors are a family of proteins that share a related DNA-binding domain and that bind to overlapping sets of target promoters. Most E2F proteins associate with a DP protein and form heterodimeric complexes that bind to DNA in a sequence-specific manner. E2F proteins control the temporal expression of genes that are needed for multiple processes during the cell cycle. Consequently, the level of E2F-dependent transcription is important for cell proliferation.

Different types of E2F complexes either activate or repress transcription. E2F repressor complexes suppress the transcription of their targets in quiescent cells, in differentiated cells and during the G1 phase of the cell cycle. When cells enter the cell cycle and proliferate, these repressors are disrupted and/or replaced by activator forms of E2F that promote gene expression.